An elite police squad fights to save the city of Los Angeles from a power-hungry East Coast mobster in this gritty police-detective film set in the 1940s, and based on Paul Lieberman's seven-part Los Angeles Times series "Tales From the Gangster Squad." Jewish gangster Mickey Cohen (Sean Penn) is a Brooklyn-born boxer-turned-L.A. kingpin whose brutal ambition has earned him the respect of the Italian mob. He's the kind of crime boss who dines with judges and police chiefs, but still isn't quite sure which fork to use when it comes time for the main course. Just when it begins to look like Cohen owns every cop in the city, however, LAPD Chief Parker (Nick Nolte) enlists honest cop Sgt. John O'Mara (Josh Brolin) to assemble a top-secret task force that will burn the vicious gangster's thriving criminal empire to the ground. With the help of his pregnant wife Connie (Mireille Enos), Sgt. O'Mara handpicks smooth-talking Sgt. Jerry Wooters (Ryan Gosling), heroin-hating Officer Coleman Harris (Anthony Mackie), deadeye Officer Max Kennard (Robert Patrick), and brilliant wireman Officer Conwell Keeler (Giovanni Ribisi) for the task at hand. Joined by Officer Kennard's tough sidekick Officer Navidad Ramirez (Michael Peņa) as they set out for their first job, the squad strike fast and hard at the core of Cohen's operation. Meanwhile, the charming Sgt. Wooters flirts with danger by starting an affair with Cohen's smoldering paramour Grace Faraday (Emma Stone). Shortly after learning that Cohen is plotting a power play that will cement his stronghold on the city, however, the squad are unexpectedly compromised, putting the lives of all of their families in danger and leaving them with little choice but to step up their efforts and target the ruthless gangster directly. Should they live to accomplish their mission, Sgt. O'Mara and his men will prevent L.A. from becoming a hive of criminal activity like Chicago or New York. But Cohen isn't going down without a fight, and if he falls, the entire city will feel the aftershock.